(1) Field of the Invention
The present invention relates generally to a method for reducing byproducts emissions from combustion reactions, and, more particularly, to a system and method for reducing nitrogen oxides (NOx) and sulfur oxides (SOx) in combustion furnaces.
(2) Description of the Prior Art
Combustion furnaces utilize injection of chemical reagents to reduce NOx and SOx and other noxious substances in the combustion effluent. These reagents are frequently dissolved in water and injected into the combustion space under pressure, forming water droplets that aid in the dispersion of the chemical reagents in the combustion gases.
In a low-relative humidity environment, the droplets will start evaporating before they have a chance to reach their boiling point. The droplets will therefore completely evaporate and make the reagent dissolved in the water droplets chemically available much sooner than the time required for the droplets to reach their boiling point. Making the reagent chemically available prematurely may lead to undesirable side reactions. In the case of NH3 and NH3-based reagents that are injected into combustion furnaces in order to react with NOx compounds to reduce them to elemental nitrogen, premature availability of the NH3 at elevated temperatures can cause them to be oxidized themselves to NOx, thereby actually raising the combustion gas NOx levels, rather than reducing them.
Prior art methods utilized large droplet sizes to delay the complete evaporation of the droplet and availability of the chemical reagent dissolved therein. However, in high-turbulence systems, droplet sizes are limited by the shear of the gases. Therefore, a need exists for a method to prevent complete evaporation of liquid droplets in a high-turbulence system until complete evaporation is desired.